UC-NRLF 


FLIES  AND  MOSQUITOES 
AS  CARRIERS  OF  DISEASE 


BY 


WM.  PAUL  GERHARD,  C.  E. 


What  Farmers  Can  Do  to  Assist 

in  the   Campaign  Against 

Flies  and  Mosquitoes 


BY 


WM.  PAUL  GERHARD,  G.  E. 

merican  Society  Mechani 
Consulting  Engineer 

Doctor  of  Engineering 


Member  American  Society  Mechanical  Engineers 
Consulting  Engineer 


(Reprinted  by  courteous  permission  of  The  Country  Gentleman,  Albany) 


New  York:  1911 

Published  by  the  Author 
39  Strong  Place,  Brooklyn,  N.  Y. 


Price  25  Cents,  Net 


Flies  and  Mosquitoes  as  Carriers  of  Disease 


By 
William  Paul  Gerhard 


It  is  now  well  known  that  the  common  house  fly  and  the  mosquito  are 
not  merely  nuisances  but  enemies  to  mankind  and  positive  dangers  to 
health  by  becoming  at  times  the  medium  for  disseminating  disease  germs. 
We  hear  much  of  flies  being  the  indirect  cause  of  typhoid  fever,  and  of 
some  species  of  mosquitoes  causing  malarial  fever.  Both  typhoid  fever 
and  malaria,  though  occurring  to  some  extent  in  cities,  are  considered  to  be 
chiefly  country  or  farm  diseases;  hence  this  subject  ought  to  interest  the 
farmer. 

It  is  not  necessary  for  our  purposes  to  explain  at  length  how 
diseases  are  transmitted  by  insects.  Suffice  it  to  mention  that  some  insects, 
like  flies,  carry  disease  mechanically  by  transferring  the  germs  by  means 
of  their  bodies,  wings  and  feet  from  human  excreta  to  our  food,  while 
others,  like  some  species  of  mosquitoes,  become  the  host  of  disease  germs, 
with  which  they  inoculate  human  beings  through  their  bite.  It  is  now 
firmly  asserted  that  one  species  of  the  mosquito,  the  anopheles,  is  the  only 
contributing  cause  of  malaria,  and  that  this  illness  may  be  entirely  avoided 
by  preventing  persons  from  being  bitten  by  infected  mosquitoes  of  this 
species. 

Taking  the  above  statements  as  a  basis,  we  wish  to  point  out  that  on 
many  farms,  in  farmers'  houses  and  about  their  barns,  flies  abound  in 
warm  weather,  while  in  other  country  localities  the  life  of  the  occupants 
of  farm  cottages  is  rendered  miserable  by  the  ravages  of  mosquitoes. 
While  both  flies  and  mosquitoes  are  bad  enough  at  certain  times  in  the 
city,  they  constitute  in  agricultural  districts  a  veritable  pest,  a  source  of 
annoyance  to  horses,  cattle  and  men,  a  cause  of  physical  discomfort,  such 
as  loss  of  sleep,  and  a  nuisance  whereby  health  may  become  seriously  af- 
fected. Let  us  see,  then,  how  far  in  rural  districts  the  evil  can  be  con- 
trolled, and  inquire  what  the  farmer  can  do  to  assist  in  the  crusade  aiming 
at  their  extermination.  Let  us  study  what  conditions  are  met  with  in  the 
country  and  on  the  average  farm,  which  favor  the  existence  and  breeding 
of  both  flies  and  mosquitoes.  Let  us  explain  what  remedial  measures  can 
be  readily  applied  by  the  farmer  who  anxiously  seeks  for  improved  sur- 
roundings. 


Flies. 

1 

house  fly,"  as 


s. 

The  investigations  of  entomologists  have  shown  that  the  "malevolent 
5e  fly,"  as  Dr.  Felt  aptly  calls  it,  breeds  principally  in  horse  manure, 


3 

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and  to  a  much  smaller  extent  in  cow  dung;  that  flies  are  not  frequently 
found  in  chicken  pens,  but  that  they  will  lay  their  eggs  in  accumulations 
of  human  excreta,  and  in  garbage,  decaying  vegetation  and  filthy  refuse. 
This  accounts  for  the  well-observed  fact  that  flies  are  specially  abundant 
in  the  neighborhood  of  stables  and  of  privy  outhouses,  and  that  dwelling 
houses  located  close  to  these  are  usually  badly  infested,  unless  they  are 
protected  as  described  further  on.  An  indirect  proof  is  afforded  by  the 
fact  that  in  cities  the  rapidly  increasing  use  of  motor  vehicles  and  the 
corresponding  reduction  in  the  number  of  stable  pits  reduces  the '  fly 
nuisance. 

•  In  poor  farmers'  houses,  a  dirty  condition  of  rooms,  walls  and  ceilings 
favors  the  invasion  by  flies.  Crumbs  left  on  the  table  and  food  particles 
scattered  on  ill-swept  floors  or  hidden  in  crevices  attract  them,  as  does  of 
course  any  food  which  is  openly  exposed.  Filthy  cuspidors  are  another 
fruitful  cause  for  flies.  A  high  temperature  of  a  room  invites  the  pres- 
ence of  flies ;  hence  they  select  the  kitchen  by  preference,  but  also  the  ad- 
joining dining  room,  and  those  bedrooms  through  or  near  which  the 
kitchen  chimney  passes.  It  is  likewise  found  that  dark  rooms  are  less 
affected  than  sunny  rooms,  and  rooms  on  the  ground  floor  more  than  those 
on  upper  floors.  . 

The  antiquated  and  most  primitive  methods  of  waste  disposal  still  exist- 
ing on  many  farms  offer  favorable  conditions  for  the  breeding  and  rapid 
multiplication  of  flies ;  neglected  privy  vaults  and  unclean  privy,  boxes,  or 
dilapidated  outhouses,  stable  and  barn  manure  pits,  offensive  overflows 
from  cesspools  into  open  ditches,  and  similar  accumulations  of  filth  and 
nuisances  are  potent  factors  causing  the  presence  of  house  flies  in  large 
numbers. 

A  mistaken  view,  altogether  too  prevalent  in  many  farmers'  homes, 
is  that  "flies  are  a  necessary  evil,"  which  is  confined  to  a  few  summer 
months,  or  that  they  are  an  altogether  harmless  nuisance.  Just  because 
the  fly  nuisance  exists  only  in  summer  and  autumn  time,  it  hardly  seems 
worth  while  to  the  farmer  to  take  much  trouble  to  fight  it !  It  is  time  that 
farmers  should  be  impressed  with  the  fact  that  where  flies  have  access 
to  disease-infected  discharges  they  may  carry  deadly  germs,  and  that  where 
they  enter  -the  kitchen,  the  pantry  or  the  dining  room,  attracted  by  the 
food,  they  deposit  the  germs  in  crawling  over  the  food,  which  they  con- 
taminate either  in  this  way  or  by  the  fly  specks.  That  the  latter  may  be 
a  source  of  actual  and  positive  danger  will  become  apparent  when  we  con- 
sider that  any  germ-infected  material  eaten  by  flies  may  pass  through  their 
intestinal  canal  alive,  and  when  deposited  on  food  may  spread  disease. 

Control  and  Extermination  of  Flies. 

The  farmer  should  resolve  not  to  tolerate  such  a  nuisance  and  the 
danger  to  health*  incident  to  it,  and  should  apply  himself  with  energy  to 
the  individual  work  aiming  at  the  control  and  extermination  of  flies. 

First  of  all,  he  should  adopt  better  methods  of  waste  disposal  and  exer- 
cise watchful  care  over  the  excreta.  To  accomplish  a  proper  disposal  of 
sewage  matters  and  of  human  excreta  as  well  as  animal  manure  in  such 


a  manner  that  they  cannot  become  accessible  to  flies  is  indeed  one  of  the 
important  problems  which  in  the  country  confront  the  modern  sanitarian. 

The  installation  of  indoor  plumbing  conveniences,  including  water- 
closets,  is  one  step  in  the  right  direction,  and  the  tendency  has  in  recent 
years  been  to  take  seriously  the  advice  of  sanitary  engineers  that  sanitary 
plumbing  should  be  introduced  into  farmhouses.  But  if  outdoor  con- 
veniences must  be  adhered  to,  let  these  consist  of  properly  maintained  earth 
closets,  the  contents  of  the  boxes  being  covered  with  lime  or  other  dis- 
infectant every  few  days,  and  the  boxes  being  removed  and  changed  fre- 
quently. And  if,  perchance,  it  should  be  necessary  to  retain  a  privy  vault, 
be  sure  to  have  its  contents  frequently  disinfected  by  sprinkling  with 
carbolic  acid,  or  with  chemical  compounds  like  lysol  or  saprol.  Cesspools 
should  receive  a  similar  treatment,  and  Dr.  L.  O.  Howard  mentions  the  use, 
originating  in'France,  of  residuum  oil -in  privies  and  cesspools,  by  which 
fly  larvae  are  killed,  the  flies  prevented  from  entering,  and  the  eggs  already 
laid  destroyed  before  hatching. 

Where  there  is  sewerage,  see  to  it  that  it  is  in  proper  working  order, 
that  no  stoppages  and  no  leaks  in  the  drains  exist. 

From  what  has  been  said  so  far,  and  also  from  what  follows,'  it  will 
be  apparent  that  the  extermination  of  flies  can  be  brought  about  chiefly 
by  a  diligent  attention  to  a  proper  disposal  of  waste  matter,  and  by  the 
maintenance  of  scrupulous  cleanliness.  Hence,  the  fly  problem  is  a  sani- 
tary problem,  and  it  is  for  this  reason  that  we  find  it  in  recent  years  • 
occupying  the  serious  attention  of  sanitarians. 

The  next  points'  to  'which  the  farmer  should  pay  attention  are  his 
horse  stables,  cow  barns,  and  manure  pits.  The  farm  boss  should  instruct 
his  farm  hands  and  the  hired  help  regarding  the  proper  care  of  these.  It 
is  desirable  that  horse  stalls  should  have  water  tight  floors,  and  in  any 
case  it  is  necessary  tc?  construct  the  manure  pits  in  cement  and  concrete 
so  as  to  be  tight,  and  to  have  them  well  covered.  All  rain  water  should 
be  excluded  from  them,  and  their  construction  should  be  such  as  to  prevent 
flies  from  entering.  The  screening  of  manure  pits  has  been  suggested  to 
prevent  flies  from  breeding  in  them,  but  where  the  pits  are  occasionally 
treated  with  chloride  of  lime,  wire  screens  will  rapidly  corrode.  This 
treatment  is  said  to  be  cheaper  and  more  effective  than  the  occasional 
sprinkling  of  the  manure  pit  with  kerosene  oil,  although  this  latter  method 
doubtless  also  effects  some  improvement.  Hence,  it  is  better  to  cover 
manure  pits  up  and  to  keep  them  dark  to  prevent  the  flies  from  breeding 
in  the  manure.  It  is  quite  important  to  prevent  the  pits  from  becoming 
filled  up  by  having  the  manure  hauled  away  at  least  twice  a  week  and 
spread  on  the  land.  *f  & 

Dairy  farmers  should  look  particularly  to  the  sanitation  of  the  milk 
house  and  abolish  privy  vaults,  outhouses,  cesspools  or  manure  pits  existing 
in  their  neighborhood.  The  contamination  of  the  milk  supply  by  flies  may 
be  prevented  by  screening  the  dairy  windows  and  doors,  which  renders 
such  a  building  practically  flyproof. 

Barnyards  should  be  kept  scrupulously  neat  and  tidy;  gutters  and 
stalls  of  stables  should  be  cleaned  daily,  all  refuse  heaps  kept  covered 


* 


pending  removal,  no  decaying  organic  material  permitted  to  accumulate  on 
the  premises,  and,  not  least  in  importance,  the  household  garbage  can 
should  be  cleaned  and  scoured  daily,  and  when  in  use  be  always  kept  well 
covered.  Garbage  should  be  stored  in  metal  receptacles  with  metal  tight- 
htting  covers,  and  all  filth-reeking  wooden  garbage  boxes  or  leaky  slop 
pails  abolished.  Do  not  permit  the  women  of  the  household  to  dispose  of 
kitchen  slop  water,  in  cases  where  there  is  no  kitchen  plumbing,  by 
throwing  it,  day  by  day,  over  the  same  spot  near  the  kitchen  door,  for  the 
spot  will  become  offensive  and  necessarily  will  attract  insects. 

Coming  to  remedies  to  be  applied  inside  the  farmer's  house,  it  should  be 
pointed  out  that  there  is  no  serious  or  real  difficulty  in  dealing  successfully 
with  the  plague  of  flies,  which  exists  in  many  places.  "The  great  secret 
of  how  to  get  rid  of  flies  is  minute  cleanliness  in  everything." 

The  up-to-date  farmer  screens  all  his  windows  and  outside  doors  to 
keep  out  the  insects,  but  there  are  still  countless  unscreened  farmhouses  to 
which  flies  have  free  access.  Of  greatest  importance  are,  of  course,  the 
places  where  the  food  is  kept,  prepared,  or  eaten,  in  other  words,  the 
pantry,  the  kitchen  and  the  dining  room. 

The  protection  which  well-made  and  well-kept  window  and  door 
screens  afford,  while  of  much  value  during  the  "summer  months,  is  perhaps 
of  the  greatest  importance  during  the  fall,  when  the  first  cool  days  appear, 
with  their  tendency  to  drive  the  flies  indoors.  Surely  it  would  seem  as  if 
it  were  more  than  a  mere  coincidence  that  this  is  also  the  season  of  the 
year  when  typhoid  fever  is  of  most  frequent  occurrence. 

It  is  advisable  to  screen  also  all  food  stored  in  the  vegetable  or  fruit 
cellar,  and  especially  to  protect  such  foods  as  do  not  require  cooking,  like 
salads,  celery,  fruit,  milk,  etc. 

The  subject  of  screening  houses  will  be  once  more  referred  to  under 
the  heading  of  mosquito  control. 

Where  a  farmer,  after  having  attended  to  the  stable  manure  pits  and 
privy  vaults,  whence  the  vast  majority  of  flies  come,  still  finds  them 
trying  to  enter  the  house,  he  should  remember  that  their  presence  is  always 
a  positive  indication  of  the  existence  of  some  form  of  filth  in  or  near  the 
premises.  Hence  he  should  institute  a  special  inspection  and  search  for 
other  breeding  places  about  or  around  the  house,  and  when  he  finds  them, 
he  should  forthwith  set  about  to  destroy  them.  If  there  are  neighbors  not 
far  away,  he  should  induce  them  to  cooperate  by  having  them  keep  their 
premises  and  yards  clean  and  burn  up  all  rubbish.  He  should  impress  them 
with  the  fact,  and  always  himself  bear  in  mind,  that  filth  and  food  are  the 
two  principal  attractions  for  flies,  and  that  their  passage  from  the  first  to 
the  second  must  be  prevented  at  all  hazards,  if  orie  \$fshes  to  avoid  disease. 

After  the  meals  all  food  remnants  should  be  carefully  removed  and 
covered  up  or  burnt.  Where  cuspidors  are  used  in  houses,  they  should 
be  kept  scrupulously  clean,  scoured  daily  with  hot  water  and  soap,  and 
disinfected  from  time  to  time. 

The  farmer  should  protest  against  the  open  exposure  of  food  at  the 
country  store  where  he  buys  his  supplies,  and  also  keep  a  watchful  eye  for 
flies  in  the  country  butcher  shop  and  on  the  itinerant  butcher's  meat  wagon. 


If  any  person  in  the  farmer's  family  is  ill,  pains  should  be  taken  to 
exclude  flies  from  the  sick  room.  The  patient  should  be  protected  by  a 
net  to  keep  the  flies  from  him,  or  else  the  sick  room  should  be  screened, 
while  flies  which  have  gained  access  should  be  removed,  caught  or  killed. 
If  it  should  prove  to  be  a  case  of  typhoid  fever,  be  sure  to  have  the 
infected  faeces  well  disinfected,  and  do  not  deposit  them  without  such 
precaution  in  an  open  privy  vault,  for  in  this  way  the  latter  may  become  a 
serious  menace  to  health. 

Flies  in  rooms  can  be  killed,  or  at  least  their  number  vastly  reduced, 
by  the  use  of  fly  paper,  either  of  the  sticky  or  "tanglefoot"  kind,  or  of 
chemical  papers  saturated  with  a  poisonous  solution ;  mechanical  traps 
and  other  devices  are  also  sold,  which  accomplish  much  good.  A  simple 
remedy,  first  suggested  by  a  Paris  scientist  and  subsequently  endorsed  and 
given  a  wide  circulation  by  the  London  Lancet,  consists  in  putting  for- 
maldehyde, diluted  in  water  in  the  proportion  of  two  teaspoonfuls  to  one 
pint,  in  a  shallow  dish  of  water.  This  solution  is  said  to  destroy  number- 
less flies.  The  burning  of  pyrethrum  or  insect  powder,  or  the  simple  dis- 
tribution of  the  powder  in  the  room  by  a  sprayer,  will  also  kill  many  of  the 
insects.  It  is  said  that  flies  abhor  the  odor  of  oil  of  lavender,  and  that 
putting  some  of  this  oil  on  a  cloth  and  rubbing  the  window  sills  and  the 
sides  of  window  frames  with  it  will  drive  flies  away.  Others  advise  keep- 
ing a  bunch  or  bag  of  sweet  clover  near  the  window.  Some  other  house- 
hold remedies  are  also  available,  and  in  cases  where  farmhouses  are  badly 
infested  with  flies  it  is  almost  criminal  negligence  not  to  make  some  efforts 
in  one  or  the  other  of  the  directions  given  to  exterminate  the  insects. 
****** 

Having  in  the  preceding  dealt  with  the  fly  nuisance  and  with  the 
methods  to  be  pursued  by  farmers  in  the  battle  against  flies,  we  shall  now 
devote  some  attention  to  mosquito  control  and  extermination. 

Mosquitoes. 

It  is  said  that  there  are  over  200  different  species  of  this  insect,  and, 
according  to  Dr.  Felt,  there  are  over  fifty  known  species  in  this  state  alone. 
For  our  purposes  this  is  not  really  material,  because  in  instituting  practi- 
cal measures  for  the  extermination  of  the  mosquito  it  is  not  required  to 
distinguish  between  the  different  kinds.  But  it  should  be  mentioned  that 
while  the  ordinary  or  domestic  mosquito  makes  itself  annoyingly  felt  only 
through  its  bite,  there  are  two  species  which  are  to  be  more  dreaded 
because  they  are  instrumental  in  the  spread  of  disease.  Mosquito-borne 
infection  concerns  principally  two  kinds  of  disease,  namely,  malaria  and 
yellow  fever.  The  anopheles  mosquito  is  now  almost  universally  recog- 
nized to  be  the  indirect  cause  of  the  transmission  of  malaria,  and  the 
yellow  fever  mosquito  or  Stegomyia  callopus  of  'the  southern  states  and  of 
tropical  countries  is  said  to  be,  according  to  recent  investigations  of 
scientists,  the  only  carrier  of  yellow  fever  germs. 

It  should  perhaps  be  mentioned  that  there  are  still  some  opponents  to* 
the  "mosquito  "theory"  of  the  transmission  of  these  and  of  some  other 
bacterial  diseases,  but  their  non-belief  is  usualty  restricted  to  the  view  that: 


a  particular  species  of  mosquitoes  could  not  be  the  sole  medium  of  trans- 
mission, and  that  in  time  to  come  science  will  determine  other  now  quite 
obscure  causes. 

Malaria  was  formerly  supposed  to  be  due  to  bad  air,  to  deadly  night 
air,  and  to  miasmas  arising  from  bad  drainage,  or  from  a  damp  subsoil 
under  houses,  or  from  newly  upturned  soil.  But  here  it  may  be  well  to 
point  out  that  nearly  all  these  alleged  causes  of  malaria  are  usually  asso- 
ciated with  the  existence  of  pools  of  stagnant  water,  or  with  swamps, 
which,  as  entomologists  have  ascertained,  are  the  very  breeding  places  for 
the  anopheles  mosquito. 

If  the  modern  mosquito  theory  is  correct,  a  person  suffering  from 
malarial  fever,  if  bitten  by  a  mosquito,  may  infect  the  insect  and  in  this 
way  the  latter  may  by  its  bite  convey  the  disease  germ  into  the  blood  of 
other  persons.  Hence  it  is  important  to  protect  all  malaria  patients  from 
being  bitten — and  this  applies  also  to  yellow  fever  patients.  Where  cases 
of  these  two  diseases  are  known  to  exist,  it  is  imperative  that  the  respec- 
tive species  of  mosquitoes  be  protected  from  becoming  infected,  for  unless 
they  have  become  inoculated  with  the  germs  of  disease,  the  mosquitoes 
cannot  convey  it  to  persons. 

In  the  coast  regions  of  tropical  and  sub-tropical  countries,  and  in  some 
of  our  southern  states,  the  special  mosquito  named  before,  an  insect  with 
striped  wings,  causes  by  its  bite  the  transmission  of  yellow  fever. 
According  to  an  article  by  A.  Dastre  in  the  Revue  des  Deux  Mondes  of 
Paris,  which  appeared  in  September,  1905,  the  yellow  fever  mosquito  can 
live  only  under  conditions  of  high  temperature,  and  dies  when  the  air  is 
cooler  than  sixty  degrees.  The  insect  bites  with  energy  only  when  the 
air  temperature  is  above  seventy-five  degrees.  Hence,  in  those  countries 
which  have  extreme  heat  combined  with  humidity,  the  Stegomyia  callopus 
mosquito  abounds,  and  yellow  fever  is  restricted  to  those  localities. 

That  yellow  fever  is  conveyed  by  mosquitoes  was  first  asserted  in  1881 
by  Dr.  Finlay  of  Havana.  Searching  investigations  and  experiments  of  a 
special  United  States  Army  Board,  in  1890  and  later,  served  to  confirm  this 
view.  Formerly  it  was  held  that  filth  favored  the  occurrence  of  yellow 
fever,  but  now  it  is  believed  that  bad  drainage  and  accumulations  of 
liquid  filth  are  only  contributory  conditions,  because  they  favor  the 
breeding  of  the  Stegomyia  callopus  mosquito. 

It  is  interesting  as  well  as  useful  to  know  something  of  the  habits  of 
mosquitoes.  These  blood-sucking  insects  breed  in  stagnant  water,  in  wet 
marshes  or  in  any  pool  or  permanent  water  accumulation,  such  as  may 
be  found  in  badly  graded  irrigation  ditches,  or  in  roof  gutters  holding 
water.  And  they  are  especially  fond  of  laying  eggs  in  stagnant  pools 
covered  on  the  surface  with  a  green  scum.  The  larvae  and  pupae  which 
develop  from  the  eggs  in  a  few  days,  live  only  in  water.  Standing  water 
of  any  kind  is  therefore  the  necessary  condition  for  the  multiplication  of 
mosquitoes. 

As  a  rule,  the  fully  developed  mosquito  flies  only  for  short  distances, 
and  the  anopheles  and  inland  mosquitoes  in  particular  are  said  not  to  travel 
very  far,  but  the  salt  water  or  marsh  mosquito  is  different  in  this  respect, 

8 


for  it  is  a  migratory  insect  and  sometimes  flies  long  distances.  Mosquitoes 
dislike  sunlight  and  prefer  darkness;  they  are  fond  of  entering  houses, 
and  of  hiding  in  dark  rooms,  or  in  dark  and  damp  corners.  They  some- 
times come  in  swarms  and  largely  so  at  night  time,  when  they  are  attracted 
indoors  by  the  burning  lights.  They  bite  chiefly  at  night,  though  some 
species  bite  also  in  day  time.  Mosquitoes  often  hibernate  in  the  cellars  of 
houses,  whence  they  emerge  in  the  spring  to  lay  their  eggs. 

The  question  may  occur  to  some  readers,  why  the  farmer  should  be 
concerned  in  the  movement  for  getting  rid  of  mosquitoes.  The  answer  is 
not  far  to  seek.  Mosquitoes  are  not  merely  a  constant  menace  to  our 
comfort,  but  some  species  may  prove  a  serious  dangef  to  our  health;  they 
certainly  interfere  greatly  with  the  comfort  of  all  people  living  in  rural 
districts,  and  what  is  perhaps  of  more  importance,  they  may  affect  their 
business  interests.  Dr.  L.  O.  Howard  of  the  United  States  Bureau  of 
Entomology  in  Washington,  asserts  that  there  are  instances  on  record 
where  the  attacks  of  herds  of  cattle  by  swarms  of  mosquitoes  reduced  the 
yield  of  milk  to  such  an  extent  as  to  render  the  keeping  of  these  animals 
for  dairy  purposes  unprofitable.  Horses  likewise  are  injured  by  the 
attacks  of  mosquitoes.  But,  more  than  this,  there  are  vast  tracts  of  land 
in  different  sections  of  this  country  which  are  rendered  practically  unin- 
habitable and  impossible  of  development  owing  to  the  presence  of  mos- 
quitoes in  large  numbers.  It  is  a  matter  of  record  that  many  places  badly 
infested  with  them  have  shown  a  considerable  depreciation  in  their 
property  value. 

Numerous  species  of  mosquitoes  are  merely,  so  far  as  is  now  known, 
a  source  of  annoyance  by  their  bite,  but  do  not  transmit  disease.  It  is 
obvious,  however,  that  for  practical  purposes  it  is  neither  necessary  nor 
feasible  to  distinguish  between  the  different  kinds  of  mosquitoes,  and  it 
would  also  be  useless  to  wage  the  war  of  extermination  on  only  one  or 
two  kinds.  Let  us  accordingly  adopt  the  much  more  common  sense  view 
that  all  mosquitoes  are  harmful  in  one  way  or  another,  and  let  us  see 
what  practical  measures  can  be  adopted  to  reduce  the  nuisance.  That  it 
is  perfectly  feasible  to  do  this  has  been  practically  demonstrated  in  several 
places,  as  for  instance  on  Staten  Island,  N.  Y.,  and  on  the  north  shore  and 
in  some  places  on  the  southern  or  ocean  side  of  Long  Island.  In  other 
countries,  too,  some  regions  formerly  almost  uninhabitable  on  account  of 
mosquitoes  have  been  made  salubrious  and  attractive.  By  proper  measures 
systematically  carried  out  in  the  Island  of  Cuba  since  1901,  yellow  fever  and 
mosquitoes  have  both  been  practically  wiped  out,  and  similar  good  work 
has  been  accomplished  more  recently  in  the  Panama  Canal  zone  by 
"mosquito  brigades,"  organized  under  the  direction  of  Colonel  Gorgas. 
On  the  Isthmus  yellow  fever  has  been  eliminated  to  a  large  extent,  and 
malarial  fever  greatly  reduced,  and  thus  this  once  notoriously  unhealthful 
region  has  been  changed  to  one  fit  to  live  in. 


It  has  already  been  pointed  out  that  malaria,  like  typhoid  fever,  is 
chiefly  a  disease  of  the  country,  and  this  is  readily  explained  by  the  fact 

9 


that  there  are  numerous  conditions  in  farming  and  rural  districts  which 
favor  the  existence  of  mosquitoes.  Near  and  about  farmhouses  there  are 
almost  always  collections  of  standing  water,  or  water-filled  receptacles 
which  form  ideal  breeding  places.  Even  small  depressions  in  grass  land, 
small  puddles  of  water,  due  to  cow  tracks  or  to  the  hoof  prints  of  horses, 
may  become  contributing  causes  of  the  nuisance.  The  back  yard  of  a 
farmhouse  offers  likewise  numerous  opportunities  for  the  pests  to  breed. 

Mosquito  Control  and  Extermination. 

Farmers  can  aid  in  the  extermination  of  the  mosquito  in  two  ways: 
first,  by  individual  efforts,  and  second,  by  combined  or  community  efforts. 
The  individual  efforts  may  be  either  preventive  or  else  protective  measures, 
and  it  is  to  the  former  that  we  desire  to  draw  particular  attention,  though 
the  latter  will  also  be  referred  to  briefly. 

The  most  important  individual  preventive  measure  is  the  abolishment 
of  all  breeding  places  of  mosquitoes.  This,  of  course,  requires,  first  of 
all,  a  thorough  search  for  these  places,  and  when  they  are  found,  the 
correct  method  of  proceeding,  the  only  one  promising  real  results,  is  the 
permanent  destruction,  and  not  merely  the  temporary  treatment,  of  the 
breeding  places.  This  was  pointed  out  by  Dr.  Alva  H.  Doty  in  his  success- 
ful mosquito  campaign  on  Staten  Island,  N.  Y.,  and  likewise  by  Dr.  John 
B.  Smith,  state  entomologist  of  New  Jersey,  in  his  efforts  to  rid  parts  of 
that  state  of  mosquitoes.  Many  breeding  places  are  the  direct  result  of 
untidiness  and  carelessness,  and  are  readily  abolished. 

The  simple  and  practical  measures  to  be  adopted  consist  in  (1)  drain- 
age; (2)  filling  in;  (3)  treatment  with  kerosene  oil  or  similar  preparations. 
Rank  growths  of  weeds  or  high  grass  on  the  banks  of  sluggish  streams, 
and  weed-protected  shallow  nooks  of  ponds,  often  conceal  some  breeding 
puddles,  and  in  themselves  form  favorite  harboring  places  for  the  adult 
mosquito.  Hence,  the  farmer  should  keep  his  lawns  well  trimmed  and  do 
away  with  all  weeds,  high  grass  and  low  bushes  or  shrubs  about  ditches, 
brooks  and  ponds.  Back  yards  and  vacant  lots  should  be  cleaned  up  and 
put  in  a  tidy  condition.  Among  numerous  places  which  collect  rain  water 
and  where  mosquitoes  will  breed  by  preference,  should  be  mentioned  ill- 
drained  roadside  ditches  and  road  gutters,  catch  basins,  undrained  bog 
holes,  all  places  where  the  natural  drainage  has  been  interfered  with, 
swamps  or  marshy  places,  depressions  or  pools  in  rocky  ledges,  newly  made 
and  water-filled  hollows  and  excavations  generally;  holes  formed  by  the 
pulling  out  of  tree  stumps,  also  holes  in  decaying  trunks  of  trees,  as  well 
as  ill-graded  irrigation  ditches. 

All  such  danger  spots  should  be  abolished  by  draining  them  properly, 
or  where  this  is  only  partly  practicable,  by  supplementing  the  drainage  work 
with  judiciously  applied  and  permanent  filling-in.  In  doing  this  one  should 
be  extremely  watchful  not  to  create  new  breeding  places. 

Places  about  the  farmhouse  where  mosquito  larvae  or  wigglers  may 
usually  be  found  are  all  kinds  of  water-containing  receptacles,  such  as  the 
following;  old  tin  cans  on  the  garbage  pile,  old  tubs,  pails  or  buckets  and 

10 


watering  pots,  garden  or  house  vases,  broken  crockery  and  glassware, 
water  troughs,  ornamental  water  gardens  and  pools  containing  stagnant 
water.  The  farmer  should  therefore  strive  not  to  leave  any  kind  of 
receptacle  lying  about  in  which  rain  water  may  accumulate.  A  single  tin 
can  or  an  earthen  jar  with  standing  water  may>  breed  scores  of  mosquitoes. 
The  roof  gutters  should  not  be  overlooked  in  the  inspection,  for  if  they 
are  not  properly  pitched,  or  have  sagged  at  a  point  away  from  the  outlet, 
or  if  obstructed  at  the  connection  with  the  leader,  they  will  hold  stagnant 
water,  which  will  attract  the  female  mosquito. 

All  receptacles  in  or  about  a  house  holding  water  should  be  either 
removed,  emptied  or  screened.  Roof  tanks,  rain-water  barrels,  under- 
ground cisterns,  sewage  tanks  and  cesspools,  also  drainage  catchbasins  of 
all  kinds  are  often  found  to  be  breeding  places,  and  hence  they  should  be 
covered  and  protected  with  wire  or  cotton  gauze  screens.  Cisterns  may 
also  be  treated  with  oil  or  kerosene.  The  water  in  watering  troughs,  and 
that  placed  in  chicken  coops  and  dog  kennels,  should  be  changed  daily. 

Wet  places  and  pools  which  can  neither  be  permanently  drained  nor 
filled  in  may  be  treated  by  pouring  or  spraying  over  them  some  common 
kerosene  oil.  The  oil  interferes  with  the  breathing  of  the  larvae,  and  thus 
suffocates  them.  The  odor  of  the  oil  is  also  abhorred  by  the  fully 
developed  mosquito.  This  method  of  treatment  applies  of  course  only  to 
still  water,  and  would  be  inefficient  for  running  brooks.  The  oil  is  a  good 
protection  while  it  lasts.  The  drawback  is  that  it  is  apt  to  evaporate  rather 
rapidly,  and  that  it  disappears  quickly  after  rain  storms,  and  hence  the 
application  should  be  renewed  every  week  or  two,  which  renders  this 
remedy  both  irksome  and  expensive.  The  oil  is  spread  in  a  thin  film  over 
the  water  surface,  and  one  ounce  suffices  for  from  fifteen  to  twenty  square 
feet.  The  treatment  of  cisterns  and  of  cesspools  with  kerosene  oil  is 
also  advisable. 

The  treatment  of  standing  water  with  crude  petroleum  oil  has  been 
found  to  have  other  drawbacks.  It  is  difficult  to  spread  the  oil  evenly,  and 
the  wind  blowing  over  the  water  is  apt  to  drive  the  oil  to  certain  spots, 
leaving  other  parts  of  the  water  surface  free  from  it.  A  better  method 
than  the  spraying  of-  the  surface  consists  in  injecting  the  oil  at  a  greater 
depth. 

Instead  of  crude  oil,  a  chemical  preparation  known  as  phinotas  oil 
(made  by  the  Phinotas  Chemical  Company  of  237  Front  Street,  New  York 
City)  has  been  successfully  used  in  recent  years,  and  found  to  be  an  effi- 
cient and  rapidly  acting  preparation  for  killing  the  mosquito  larvae.  This 
oil  is  prepared  from  crude  petroleum,  but  differs  from  it  in  having  the 
property  of  sinking  to  the  bottom  at  first  and  subsequently  rising  to  the 
surface.  The  small  globules  of  this  oil,  after  breaking,  diffuse  themselves 
over  a  large  area.  In  some  cases  it  has  been'  distributed  by  means  of  a 
pressure  or  force  pump,  operated  by  hand.  Experiments  made  in  New 
Jersey  with  this  liquid  have  shown  that  the  treatment  need  not  be  applied 
oftener  than  once  every  four  weeks,  hence  it  requires  less  labor,  and  thus 
becomes  a  cheaper  remedy  than  the  application  of  kerosene  oil.  The  phino- 
tas oil  is  also  said  to  be  useful  in  the  treatment  of  cesspools. 

11 


Another  measure  which  has  proved  effective  in  many  cases  is  to  stock 
the  ponds  or  pools  with  small  fishes,  such  as  minnows,  sun  fish  and  gold 
fish.  These  eat  the  larvae  and  eggs  of  the  mosquito.  To  render  this 
remedy  successful,  it  is  necessary  to  dig  out  and  deepen  all  shallow  edges 
of  ponds,  and  to  trim  the  vegetation  along  their  margin,  in  order  that 
the  fish  may  reach  the  breeding  places. 


The  farmer  should  also  apply  measures  for  the  extermination  of 
mosquitoes  within  his  house  and  barn.  If  a  careful  search  shows  the 
rooms,  the  cellar  or  the  barn  to  harbor  mosquitoes,  the  insects  may  be 
driven  out  or  done  away  with  by  burning  pyrethrum  or  insect  powder, 
the  fumes  from  which  stupefy  them.  They  should  then  be  swept  up  and 
burned  in  the  range.  A  mixture  of  equal  weight  of  gum  camphor  and 
pure  carbolic  acid  in  crystal  form  may  be  evaporated  in  the  rooms,  in  the 
proportion  of  three  ounces  to  1000  cubic  feet,  but  the  liquid  is  inflammable 
and  the  fumes  are  poisonous,  hence  great  care  should  be  exercised  in 
applying  the  remedy.  Another  remedy  consists  in  spreading  oil  of 
pennyroyal  on  a  blotting  paper,  which  is  placed  either  on  the  window  sills 
or  about  the  room,  or  on  the  bed  pillows  in  the  case  of  bedrooms;  spirits 
of  lavender,  used  on  a  handkerchief,  are  also  said  to  drive  mosquitoes 
away.  Tobacco  fumes  and  lighted  Chinese  punk  sticks  may  be  helpful  in 
this  respect,  and  the  use  of  naphthaline  or  moth  balls  also  repels  the 
insects. 

A  careful  search  should  be  made  in  the  cellar  for  any  hibernating 
mosquitoes.  Fumigation  with  sulphur  or  with  formaldehyde  should  be 
resorted  to  in  order  to  clear  the  cellar;  if  there  are  any  drain  openings,  or 
floor  cesspools,  these  should  be  freely  sprinkled  with  kerosene  oil. 


The  protective  measures  against  mosquitoes  are  perhaps  fully  as 
important  as  the  preventive  measures  spoken  of  thus  far.  In  order  not 
to  attract  the  insects  at  night,  it  is  advisable  not  to  use  a  bright  light  in 
bedrooms  when  retiring.  One  should  always  avoid  sitting  outdoors  at 
night  in  mosquito-infected  districts,  in  order  not  to  expose  oneself  to  the 
bite  of  the  malaria-carrying  insect.  One  of  the  best  preventives  against 
mosquito  bites  is  the  use  of  oil  of  citronella,  diluted  in  olive  oil. 

Windows  and  outside  doors  of  farmhouses  should  be  carefully 
screened  to  keep  out  the  mosquitoes.  The  screens  may  be  either  metallic 
or  consist  of  the  cheaper  gauze  or  cotton  netting,  and  the  screen  doors 
should  preferably  have  self-closing  spring  attachments.  Beds  may  be 
protected  with  mosquito  netting  or  canopies.  The  proper  screening  of 
farmhouses  is  a  very  important  measure  of  protection;  hence  it  is 
desirable  to  know  where  to  obtain  satisfactory  screens.  Well-known 
screens  are  those  made  in  wooden  frames  by  E.  P.  Burrowes  of  Portland, 
Maine,  and  the  metal-frame  screens  manufactured  by  the  Higgins  Manu- 
facturing Company  of  1133  Broadway,  New  York  City.  The  screens  of 
both  firms  are  excellent,  but  rather  high  priced. 

12 


Other  screen  manufacturers  are  the  Cincinnati  Manufacturing  Com- 
pany, the  Watson  Screen  Company,  Jamestown,  N.  Y.,  and  the  Roebuck 
Wire  Screen  Company  of  Brooklyn. 

The  Invisible  Roll  Screen  Company  of  East  Avenue,  Long  Island  City, 
N.  Y.,  makes  a  novel  rolling  screen,  consisting  of  an  all-metal  frame,  to 
which  rustless  wire  cloth  is  attached.  It  rolls  up  like  a  shade  and  is  said 
not  to  get  out  of  order  easily.  When  the  window  is  opened,  the  screen 
can  be  rolled  up  with  the  sash,  and  when  it  is  closed,  it  rolls  out  of  sight. 
A  somewhat  similar  device  is  the  Jamestown  rolling  screen,  sold  by 
Carroll,  Entwistle  &  Company,  1261  Broadway,  New  York  City.  This  is 
fastened  both  to  the  window  sill  and  to  the  sash,  and  when  the  window  is 
raised  the  screen  unrolls.  The  screen  is  fastened  to  a  patented  roller, 
which  is  attached  to  the  sill,  and  when  not  raised  it  remains  concealed  in 
a  light  metal  box.  The  screen  does  not  consist  of  metal  wire,  but  is  made 
of  a  specially  woven  fibrous  mesh. 

Even  the  less  prosperous  farmer  can  protect  his  windows  with  home- 
made screens  of  cotton  gauze,  and  he  will  be  amply  repaid  for  the  rela- 
tively trifling  expenditure  by  the  increased  working  capacity  obtained  from 
an  undisturbed  sleep.  Many  farmers  are  not  sufficiently  informed  about, 
and  hence  not  ready  to  appreciate,  the  importance  of  keeping  the  insect 
pests  out  of  a  house,  hence  this  form  of  protection  against  both  flies  and 
mosquitoes  should  be  encouraged  by  experiment  stations  and  by  boards  of 
health  as  a  sanitary  measure. 


Much  more  effective  work  in  mosquito  extermination  can  be  accom- 
plished by  the  combined  efforts  of  farmer  communities,  and  this  applies  in 
particular  to  the  salt-marsh  mosquito.  The  wide-awake  farmer,  who  is 
bent  upon  securing  good  results,  requires  the  intelligent  cooperation  and 
cheerfully  rendered  assistance  of  his  neighbors.  With  this  in  view,  he 
should  endeavor  to  persuade  the  owners  of  neighboring  farms  to  follow 
his  own  example  in  carrying  out  the  individual  efforts  described  hereto- 
fore. In  farm  villages,  improvement  societies  should  be  formed,  one  of 
their  objects  being  the  organized  war  against  the  mosquito  pest.  The 
work  of  such  a  society  should  be  laid  out  and  directed  by  one  responsible 
head,  and  it  is  desirable  that  he  be  a  practical  sanitarian.  Much  of  the 
work  to  be  done  is  of  an  engineering  nature,  such  as  the  ditching  of 
marshes,  the  proper  grading  of  gutters,  etc. ;  hence  the  assistance  of  an 
engineer  familiar  with  drainage  work  is  much  to  be  desired.  A  beginning 
in  the  work  should  be  made  by  calling  upon  each  farmer  member  of  the 
society  to  make  individual  efforts  about  his  own  premises  to  get  rid  of  the 
mosquitoes.  Once  a  week  each  member  should  make  a  thorough  inspec- 
tion of  his  entire  premises  with  a  view  of  finding  neglected  spots  which 
might  form  breeding  places,  and  also  with  a  view  to  enforcing  cleanliness 
and  tidiness. 

Each  member  should,  of  course,  be  required  to  carry  out  on  his 
premises  the  individual  efforts  recommended  heretofore.  After  that 
should  come  the  cooperative  efforts,  comprising  chiefly  measures  directed 

13 


against  the  eggs  and  larvae  of  the  insects,  for  the  destruction  of  these 
materially  assist  in  reducing  the  number  of  mosquitoes.  To  accomplish 
effective  results,  a  general  map  should  be  prepared,  on  which  the  principal 
breeding  places  and  places  infested  with  mosquitoes  should  be  clearly 
shown,  such  as  old  mill  ponds,  swamps,  all  large  water  pools,  sluggish 
streams,  and  salt-marsh  areas.  Once  this  map  is  available,  a  comprehensive 
plan  of  campaign  can  be  laid  out. 

The  cooperative  work  recommended  comprises  the  drainage  of  marshes 
by  ditching  and  connections  with  some  nearby  water  channels ;  the  drain- 
age of  unhealthy  swamps,  the  improvement  of  gutters  on  public  roadsides 
and  the  filling  in  of  all  low  places  and  of  unsightly  and  unwholesome 
puddles  of  water.  The  work  should  also  extend  to  looking  after  cesspools 
and  rain-water  cisterns,  and  any  sewer  catchbasins,  as  well  as  public  road- 
side watering  troughs  or  fountains  should  not  be  forgotten.  In  many 
cases  the  application  of  kerosene  or  phinotas  oil  will  bring  some  improve- 
ment. The  guiding  principle  should  be  to  do  whatever  is  done  in  a 
thorough  manner.  The  active  work  might  profitably  be  supplemented  with 
instructive  lectures  on  the  subject,  and  with  the  distribution  of  pamphlets 
and  circulars  like  the  "Mosquito  Brief,"  issued  some  years  ago  by  the 
American  Mosquito  Extermination  Society. 


BIBLIOGRAPHY. 

A  partial  Bibliography  on  "Flies  and  Mosquitoes  as  Carriers  of  Dis- 
ease," compiled  by  the  author,  may  be  found  in  the  February  and  May, 
1909,  numbers  of  the  Entomological  News  of  Philadelphia,  Pa. 


WM.    PAUL    GERHARD,   C.    E. 

Consulting  Engineer  for  Hydraulic 
and  Sanitary  Works 

Member  A  merican  Society  Mechanical  Engineers 

Doctor  of  Engineering 
SPECIALTIES: 

Sanitation  of  Buildings,  Towns,  Building  Sites;   Public  and 

Domestic  Water-supply;  Sewerage,  Sewage  Disposal, 

Land    Drainage;     House     Drainage, 

Plumbing,     Ventilation;     Fire 

Protection,  Sanitary 

Inspections. 

Expert  Reports  Specifications 

Superintendence 

Forty-Second  Street  Building 

797?       Nt>w   York  City 


SOME   RECENT  WORKS 

OF 

WM.  PAUL  GERHARD,  G.  E. 

Doctor  of  Engineering 


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THEATER  FIRES  AND  PANICS,    THEIR   CAUSES 

AND  PREVENTION Price  $1.50 

THEATERS:  THEIR  SAFETY  FROM  FIRE  AND 
PANIC,  THEIR  COMFORT  AND  HEALTHFUL- 
NESS  Price  $1.00 


Soon  to  be  Published: 

KITCHENS  AND  LAUNDRIES,  THEIR  PLANNING,   EQUIPMENT  AND 
SANITATION.    Illustrated. 


UNIVERSITY  OF  CALIFORNIA  LIBRARY, 
BERKELEY 


THIS  BOOK  IS  DUE  ON  THE  LAST  DATE 
STAMPED  BELOW 

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' 


BIOLOG* 
LIBRARY 


UNIVERSITY  OF  CAIylFORNIA  LIBRARY 


